fix(xapi/VM_destroy): ignore missing VM.set_is_default_template
fix(xapi/VM_destroy): ignore missing VM.set_is_default_template

Introduced by 5f1c1278e

lmcro/xo-web,vatesfr/xo-web,lmcro/xo-web,vatesfr/xo-web,lmcro/xo-web